Automatic telephone system



Aug. 3, 1943. w. T; POWELL 2,325,877

AUTOMATIC TELEPHONE SYSTEM V v Filed March 11, 1942 1l Sheets-Sheet l1NVENTOR.

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AUTOMATIC TELEPHONE SYSTEM Filed March 11, 1942 11 Sheets-Sheet 4 n H#'11 v Www/10o L 102 5H u gils-{Ij- F175 l wwf/2mm@ INVNQR." l

Aug. 3, 1943; w. T. POWELL AUTOMATIC TELEPHONE SYSTEM Filed March l1,1942 11 Sheets-Sheet 5 WWA fw in i166 C ONA/E C TO? L /NK Aug. 3; 1943.i w, T. POWELL 2,325,877

AUTOMAT IC TELEPHONE SYSTEM Filed March 11, 1942 l1 Sheets-Sheet 6 TR 57'0 L//VE CCT K l ,-M

L /A/E C O/V/VE C TOE INVENTOR.

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AUTOMATIC TELEPHONE SYSTEM Filed March ll, 1942 ll Sheets-Sheet '7 2.05'204 /203 I ,237 i T52 20 @wml C/IM CM 2 f5 257/ CL 0550 Eva-2y CM2 CTQs/4 M/MFO@ 2 SEC. v H F i l TL FLL Wu-254 25511226 IN V EN TOR.

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Aug. 3, .1943. w. T. PowELl. 325,877

AUTOMATIC TELEPHONE SYSTEM Filed March 11, 1942 1l Sheets-Sheet 9 H Iscf/0 @CJ I J'wfs M60 I f3 /fai w. T. POWELL 2,325,877l

Fiied March 11, 1942 11 sheets-sheet 1o l ,Tl I I l l I l v I 22oINVENTOR Aug. 3, 1943.

AUTOMATIC TELEPHONE SYSTEM w. T. POWELL 2,325,877 n AUTOMATIC TLPHONESYSTEM Filed March 11, 1942y 11 sheets-sheet 11 Aug. 3, 1943.

Patented Aug. 3, 1943` AUTOMATIC TELEPnou'EsYsTEn/r .Winfred T.PowellyRochester,N.'Y., assigner to The Stromberg-Carlson" TelephoneManufacturingV Company;

tion of NewYork.

Rochester, N. 'Y., a corpora- -Appneaiion Mareuil, 1942, sri'ai 1%.434,246;

(o1.` 17a-11n] t Y 122 claims..

This invention relates toV automatic --telephone systems andparticularly tor-communicationv facilities furnished by small Vcommunitydial -ofiices at which a plurality of party` telephone lines terminate.An object of the inventionis 'to pro-V vide a System of 'this'kind thatis economically constructed,

simple in 'operationAY and VVVeasily Vmaintained Y It is a furtherobject'of` the to provide, foruse in a system ofthe all-relayv presentinvention type, automatic line selecting and-connecting'i equipmentwhich is fully selectivein character,

and which requires a minimum number ofl relays for its operation. Y. Y.

lt is another object of the invention to'provide an improved allotterordistributor arrangement associated with the all-relayrnder links,whereby the lines are divided into sub-groups, with the lines in eachsub-group being normally served bythe line finders of the associatedsub-*groups and with an automatic group transfer arrangement which iseeotveto transfer calls from lines of Va particular sub-group into thefinders of the non-associated sub-group in the case' oflousy` or troubleconditions. i it is a further object of the` invention to pro- Y vide animproved marker and lockout arrange ment, which is so arranged that'-simultaneous calls in a sub-group of lines will not cause faultyoperation of the equipment, such as selectingv more than one line byAa-single'n'der or selecting one line by more than one iinder.

It is an additional yobject of'the invention to provide an automaticringing machine transfer arrangement, whereby a trouble condition'in thecommonv ringing or interrupter apparatus is effective to automaticallyswitch over to the. other or reserve ringing equipment. 'Y f Anotheradditional object ofthe invention is to arrange the circuits of thecommon'rin'ging equipment so that a toll operator, or other party havingauthority to make such connections, can dial special numbers forswitching from one ringing machine equipment to the other, butordinary'subscribers in the system cannot connect with these numbers foreffecting such a transfer. in this connection, a signal is given toindicate to Athe Voperator which machine is in` operation.

Further features of the invention pertain to 4the particular arrangementof the circuitelew' lments'whereby the above outlined andadditionaloperating featuresY are attained.

This invention has been illustrated inthe accompanying drawings inwhich:

. 'Fig l shows a plan for arranging the various other figures of thecircuits;

,. .Fig 2 shows a line' circuit anda portion of y the t `common lmarking and lockout, circuits;

.. Fig. 3 shows asui''ticient portion of the comino allotter circuits'for each sub-group ofv'linesto obtain an` understandingyof the presentinven. t

tion;

Fig. 4; shows f a order named and .with correspondingly-numbered linesin circuit;

Fig. 7 shows a portionrof the line connector which is associated witheach connector link; i

"Fig indicates the common time release circuit,fwhich is for the purposeofV automatically releasing a Derma-nenti Vfrom .thef'connector link;v i

lease arrangement, for the purpose of automatically Vreleasing atalkingconnectonaftery aprev Figs.1l and 12 show' the relay typereverting t call vcircuit; v i.

Fig fl'lA is al chart'illustratingv the counting relays left operatedafter Vthe` 'va1iou.s impulses Fig. 13\is"a blockAY diagramand singleline layout of the system.

A detailed description wiunow beiniade f a call which is 'assumed tobeestablishedfromfa calling subscriber A to a called subscriber'.Removing the receiver at the calling station j `closes a circuitfor-operating line relay LR, which i extends from positive battery,upper winding of relay LR, back contact i8 of lockout relay LO', overthe linecircuit, by way of back f contact I9 of relay LO and lowerwinding or" relay VLR. to

negative battery. Relay LR'closes a circuit for operating tens lockoutrelay TLOEI,Y which exeY tends from positive battery, back contact 2| ofrelay TLOE! and back contactsl'of all other'tens lockout relays inseries, back-contact 22 vof relay TLOZI, winding `of relay TLOZI,backfcontact y23 of cut oli-relay CO, front contact 24" of frelayf LRand"A upper winding of relay LO -to negative battery. Relay TLO2Iloperates over this circuit and,` at back Contact 2| opens theabovedescribed series circuit so that no other TLO relay portionof alineiinderlcircuit, with-the connecting portion of Va selectorillus-.trated; X f- Figs. 5 andVv 6,when placed together inthe alinementshowla connector'link Y Fig. 9` shows the circuit oi a modiedftimere'- ferrelay vGrTF normally energized. Ii the call in this second sub-:group ishandled in a normal manner, the closure of-back contact 12 of relayfinder, orthe ISA relay does not'extend positive battery back overthesleeve conductor vfor operating the CO relayof the v.calling line,v thenthe dash-pot relay has time tooperate. In the above and its contact 35switches the start wiretircm `conductor 31 to conductor 11, which leadsthrough back contact 18 of relay-I IAL oi the second allotter group tooperate vrelays I IALP and! IALG.

This connects' conductors 4I and 45 by way of front contacts 'IllA and15 to finder relays of the vfirst finder in the second sub-group. Thenthe finder relays and the associated CB and SA relays operatein a mannersimilar tothat above de scribed, with the call being handled bythe nderin the second sub-group;

In the event that the call originates in the' second subgroup and that`the calling line fails to beY fprOperlyiOund, the #2 dash-potvrelaywill operate for veffecting the operation or" relay A2DPR, and thisrelay in turn switches Vthe start .wire 16 of the second group fromconductor 11 to conductor 31. This' is effected kby Contact 1910i YZGTFenergizes the;#2,dashpot relay but this Vrelay doesnot have time toVclose itsiront con- .tact 13. AIn the event that, due to some faultycirv cuit condition, the 'calling line is not. extended :through totheICB and'ISA relays 'of the line circuitsif desired. f

have progressed through all the-iinders in the 'associated subi-group.It will ,be understood; that relays IDPR' and ZDPR can ycontrol alarm1t' win be notedthet theopera'uen of relay IALG closes a circuitatitsirontc'ontactv 210 byA Y way of boosterconductor BR for operatingreel example this eects the operation of relayIDPR relay ZDPR and theenergization of conductor Si allots a finder in the iirst sub-group. 1;',Y

It is believed that the above explanation indicates howV calls; in eachof the two sub groups'r are normally handled by finders in theassociated sub-groups' and how, in the event of a "faulty condition, afinder of a normally non-associated sub-group willcstep in and takecarel of thecall. The circuitsare also arranged so that,

inthe event allv iindersrin' a` sub-group are busy,kr

the start wirewill ,be Vvextended to a nder in the non-associatedsub-group. For example, in Vthe case of the above assumed call, if alliinders of the first sub-group are busy all of the .allotterrelays shownin the lower portion Vof Fig; 3, such as relays IAL, 2AL and BAL will beoperated.v

Now when positive battery yis applied to conductor 31asgabove".describedfthe circuit ,ex"

tends through front contact 38V ofrelay IAL,

contacts of all other AL relays and back contacts of all otherrALPrelays to conductor 11, which .leads to contact Y13 of relay IIAL andthence to the alloter relaysof the non-associated subgroups A similarcircuit extends through front contacts of .the AL relays and backcontacts of the ALP relays of the upper' subi-group to conductor B0 andthence to conductor 31, which carries this starter wire from the uppersub-group toA the allotter relays of the lower sub-group. twill be notedthat there-is a circuit completed through front-*contact 82 of relayIDPR and front Contact SI of relay IALP to the upper winding of. relay'IAL. This circuit, *and other similar vcircuits to other AL relays, isfor-the Vpurpose ci operating the AL relay and thus making theasseeiatedender busy m the event that Jme ALP relayallotts a certainVfinder and, due to a faulty condition, lthe connectionis not properlyhandled Y by this finder. vIln ,other words, when lrelay lIALP operatesand then, due to such a faulty condition, relay IDPR operates, relay IALis operated and locked to make thisflnder busy lto thenext call.' Itvvill be evident that this of relay ECB, kthus operating this'relay,,whichV .closes a circuitvat its front Contact S3 forpperatlay ICB,which circuit is independent r`of the calling line. This'is for thepurpose of posi- .f

tivelyoperatingthe CB relay of the finder, so the allotter and marking:relays will be sure vteclear out and notlockout succeeding calls inYthejevent of a 4high resistance leak on some'kfline'which` notioperatethe.

would 'operate relay LRbut CB relay.

, it win be assumeatnet thefeaning subscriber loperates his dial .toselect substationB of Figi. 7

The rst turn of which is assumedl to be #2321. the dial operates therst` selector (notl shown) of the ,system to selecta connector link ,inthe second hundreds group; When thisselectionY is made, inV a mannerwhich is wellfunde'rstood I by those skilled inthe' artycontacts 83, S4and 850i Vthe selector are closedY to "extendjthe tip, ring and sleeveconductors oli-the1callingI line to conductors SE,- 81,1 and y83 of theconnector link shown in Fig. i5. -Llhis extension of the tip and Yringconductors isk byV way of'ront contacts YSQ Y and 9i) of relay LCO'cfgFig. fl, which/relay-fis the usual cut-throughY relay of ktheselector-,and which operatesV when l the.` vfirst selectoroperation hasbeen completed.v

The extension ofv the closed ingeline to conductorstV andgSfoi theconnector link .completes a circuit, including :thej

calling line, by way of back contacts 9i and,y S2 of lanswering bridgerelayrABftothe wind-ings,

ing relay 2SA. The operation of relay-2SA closes a Vcircuit at itsfrontfcontact 95 for operating slow acting repeater relay SAP. vThecounterv preparing Arelay CX is now; operated fever la, c'ir'- lcuitextending from positive battery, frontconvtact 95 of relay SAP, backContact' l 2li of counter release repeaterrelay CRLF, fback contact l258backc'ontact I of Yrelay IALPA andsimilar front oftripy relay VTR;conductor` i1',- backjcontactsf I 5in series oi'allY counting'rrela'ysfromf C Ojto i CI inclusive, which includes b ackontacts Stand:91,andfwinding of relay CXzto'fn'egative, bat,- tery. The operation.ot-relay CX prepares VVfa- ;locking circuit for itself whichv iskeiectivei maintain this relay operated `atfthe timeV of theYtransmission of thenrst impulse, this locke I ing circuit extending`kfrom positive'battery, Ifront contact 95 of relaylSASE,'backcontact18ofgree' lay 2GB, conductorvl, frontcontact lli-i and winding of relaykCX to fnegative'loiattery." This locking circuit` is established Vtomaintain relay CX operated during thetransm'isson of thei first impulseof the seriesgaand` similar locking c-ircuits are providedior theothercounting Are'- lays to maintain a counting relay 4operated dureingthe transmission of animpulse which operates the next succeedingcounting-relay;A It

was `assumed that called sub-station Bfisl selected` by dialing #23%.V.'ijhisemeans that r the Yrst digit, #2, operates the selector to'select an idle connector in the groupQthat the second particularfinder: willV remain busy until calls` circuit ofthe ,eau-

After relay CRLP releases, :following Ythe loperation of relayUCLrel'ayf TF2 is voperated* over a circuit extendingfror'n positivebattery', Afront contact V| l8- of relay SAP, `Winding of relayTFZ,

conductor |313, front Contact |29 and winding of relay 4UCZ to negativebattery.V During the interval between thel release ofv relay CRLandrelay CRLP, relay C2 is released ,and after relay `CRLP releasesrelay CX isenergized VAover its previously 'lo described circuit. A

Within the interval` betweenth'e operation of relay UC2 andthe-operationof Yrelay TF2, which tact lfmL of relay SAP, -froiercontactma angl Winding of vrelay' vRI tdnegative battery through interval is ofcomparatively'longtirne'dueitothe slow release of relay`V CRLR/a test1islmade of the called line. If this line is idle, there is.,v an absenceof positive potential on its sleeve con'- ductor |3|. Then Wher'rela'yTF2 operatesjpositive potential is applied to sleeve conductor' 13| frompositive hatteryg'iront contact 95 of relay SAP, back contact|32"of'-relay BY, `iront con# tacts |33 and |34 of relays TF2 *and'TFLconf ductor SI, front contact |36`of relay U02, front contact |31 ofrelay-TG3, to conductorI I3l. This .operates the cut-oir relay of the'called line and 'also makes this line busyrto other, calls.

In vthe event that the called line1V is'busyY Vvvhen this called linetest isfm'ade, Vthep'ositive battery on conductor |3| extendsthroughfront contacts |31 and |35 of the line connecting'relaysgconductor SL,front contact |3401 relay-TPI ,'f back 'f contact|33 of relay'TFL/backContact ofv the make-before-break combination |38 and Winding of busyrelayBY toY negative battery. This operates relay BY and,'at its backcontact VllLffp're- 1 vvents theapplication of positive batteryltoconductor |3| while relay BY is maintained-locked overra circuitincluding front contact |38 'of its rmake-before-loreakcombinationrandrfront contact $5 of relay SAP. The busy tone isconnected to the calling line over a-circuit includof relay RI andcondenser M3 to [the calling line. The release of the connection-Will'bethe sameas Will be described inV conneotionwitha call to'a'lline whichis not busy.` Relay RI is operated when the station digit `is dialedaswill be later.exilail'ied4 I Y, Assuming thecalled line to be idle,'thenthe circuits functionas will now be described.' Folrlowing thetransinissionv of thefuni'ts digit, as

above described, the station digit is transmitted, which in the assumedcase is #1L Thevtransmission of the station digit' eiTects the-operation'of V.ringing relay RI at the beginning of this sta-r f4() ing frontcontact-|39 Vof relay BY, v,back contact |48 of relay CI, condenser 14|,frontconta'ct |42.

tion digit transmission,.whether the calledY line is busy or idle. thebeginning of the iirst station impulse, relay CX vis locked operatedandrelayv C|`isY operated and locked as previously described.` At'theend.of this impulse, relay CX is released and, since 'it is assumed thatone impulseis transmitted,

relay CI remains operated for selecting '16 cyclev ringing current.Relays CHQLCRL and-CRL?? operate at the beginning of the rst impulse,

when relay CBis released, inthe previouslydescribed manner.

i lRelay RI is operated over a circuit Which ex`- tends from positivebattery, front contact ||8 of relay SAP, frontv contact |S of 'relayCRLPjfron't contact |29 of relay TF1, front contact |44 of relay TF2,Vback Contact Aof relayCI, winding oi relay RI and resistance .|35 tonegative bate tery.; A locking circuit isicl'osed '1.-for'relay RI whenrelay 20B releases at l' `cn ,the line with stations digits `1l to 5Will'have n' their ringers connectedbet'ween the-tip side and- Y groundandthcse with stations digits 6 to G will which extends from positive*batterygfront `con- '15 resistance |35. It will be understoodthat'th'ese" operating Vand locking circuits for relay;l RI` arecompleted when the stationdigit'is vtransmitted i Y even though thecalled line is'busy. -When the called line idle, the reieaseorreiayoHo-at 'y 4the endof thestation-digitgcloses a-circuit -foroperating relay CI which extends from positive battery', vfront' contact95 *"of relay SAP, winding of relay CRL, back contactofmake-before-break l 'spring combination H0 of'relay C HO, front contactlas o f vrelay enne-ont Contact of relay z Y.

TF2, baci: contact |13] otrelay BY and Winding of relay CI to negativebattery. Sincevthe Winding 'oil' relay CRL isincludediin 'series' 'withthe winding of relay CI, bothjrelays are maintained operated andconsequently relayCRLP'is maintained operated overfav circuit includingironty contactyl |2-of relay CRI. Y

It'\vill be understood'that tacts |56 land llzof'relays TO3v and UCZ,con- -ducto-r RL, front lcontacts "|58 :aL-ndY |59 of relays Q'CI" andRI, back Contact it@ ofyrela'y RV to posi- =tive batteryv and thencetothe'other side of the `ringing source.r f l In' theV event that relay'RV :to v negative battery. 'Relay RV is locked-operated by means lofitsilmake-before-Y break spring combination to positivebatteryY at contact35' ci: relay SAP. Theconta'cts I5! and' lii reverse therconnection tothe'ringinglsource so thaiJ ringing current is sentoutover'the-ringsi'de'of the line. Thisis elective'to lprovidedij-` l f vided circuitringing by applying ringing current.n

to the tip side of theline Whenlthe stationdigit .is 1v to 5 inclusive'andbyapplying' ringin'gf.cur' rentto the ring sideof the rIirLe'Whenthe stationl digit is 6 or more', Y In' this "eventpthe `stations havetheirv ringersl connected between the-ring sidel and ground. a 1.V y liV-henfthe.calledfpartyl answers, relay TR is operatedland, at its frontcontact lshort 'circuits relay RI for releasingthis relay. The relleaseyof relay RI'opens up the circuitto the ringing currentfsourceatfront contacts |52 .and

'.l-illand extends `the circuitV ofthe calledlineY throughback-.contactslnlZ and V|59 to relay AB.k

Talking .current is suppliedto the called vline' .through .thewz'ndingsoi relay AB, talkingcuri .rent-issupplied Vtothe calling' line through.the f other'station digits tareeiie'ctive 'to vselectotherfrequencies-for application to the calledline vby' the diierentcoin-f.binationsof impulses in these other station digits operatingdiiierent'ccrnbinationsfof 4counting re-V the. station digit isl 6 to-Oinclusive, then relay1RV- :willY be uoperated 'over a Vcircuitextending'iromzthe'positive battery Which operates' relayl C5,vconductor l2, front ContactY 'l'l'rof relay. R,l.backcontactlandzvvinding' 'ofYAY Adescribed circuit including conductor |92After the transmission of the first digit into the reverting callcircuit, the record is transferred tothe register relays, Ri to R8inclusive. In the present example, With'lO impulses transinitted andwith counting relays Cil' and C6 operated, the corresponding registerrelays R4 and the :operated register relays. It Will be apparent thatany other combinationof impulses kfor theV rst digit dialed Willo-perate other combinations ,j f

`of'counting relays andleave the combination op- R5 will be operated.The circuit for eiecting the operation of'these register relays will nowbe described.

At the beginning of the transmission of the first digit as abovedescribed, a circuit is closed for operating relay ECHO, includingconductor |35, which was energized to operate the iirst counting relayat the beginning of' this digit.

Relay SCi-IO closes a'circuitfor operating relay f SCRL which extendsfrom positive battery, front Contact i i3 of relay SSAP, winding 'ofrelay SCRL,

front contact |93 of relayY SCH@ and resistance |90.'- to negativebattery. .A circuit is now closed for operating relay 3CRLP whichextends from register relays R4 and RS Will be operated, the

circuit for operating relay R4 extending from positive battery, frontcontact ll ici relay SSAP,

winding of relay SCRL, back contact of the makebeiore-break springcombination |93 of relay SCHC, iront contact |53@ of relay SCRL, back Lcontact le? of relay 3'Ill, conductorV .295, front contact 5&5 of relay304 and Winding of relay Rii to negative battery. Since the winding civrelay SCRL is included in this circuit, this relay remains operateduntil a short time later. circuit for operating relayRii includes thatabove by way of front Contact 296 of relay 30S and Winding of relay R5to negative battery. The closure of front contacts 2M and 2680i relaysRil and R6 completes locking circuits for these tivo relays whichincludes conductor 'fland extends by Way of back contact 2M of relay3TF| and iront contact 2|! of relay CRLP to positive battery atfrontcontact 2HE o relay 3SAP. This circuit to positive battery atcontact 2i2 extends back to the right hand termina-l of relay ECRL byway oi conductors 2&9 and |95, and since this relay has positive batteryon its left-hand terminal from front contact it ofl relay SSAP, itisshort-cir- Y;

is opened before back Contact i'ii of relay SCRL-P is closed and thisrer-doves postive battery from..

conductor |718 to effect the release of the operated counting relays.Now when relay {CRI-P releases and closes its back Contact l'i'l,positive battery is again applied toV conductor llt for operatingrelai/@CX to prepare re'- lay circuit for the'next digit. v

has been transmitted. Relays ECHO, AtCRL, and SCRLPY are. operated andreleased in sequence as Before relay SCRLP'releases, the above describedconnection toV positive battery on conductor 259 appears on bothterir-.inals of the Winding of relay 3TF. When relay BCRLPreleases andopens its contact 52| l, this positive'battery is removed from theright-hand terminalo relay 3TF| and this relayop'erates` in series witherat'ed Which corresponds to the number effimpulses in the digit and',at the end of theseries ofimpulses, the combinationof register relays.Will bel operated which corresponds to. thercombination of countingrelays left'operated. .This

also applies to the second digit dialed, which digit corresponds tothat` of the called telephone,` and inthis example it will be assumedthat thestation digit of the called telephone is #2. l i

The `transmission of the tWo impulses eiects the operation and releaseofcounting relay 3C| andjjthe operation of.. counting relay SC2 whichremains operated after this seriesV of impulses before.v When relay.'iCHO releases, a circuitjis kclosed from positive battery, frontcontact '|16' of relay. 3SAP, Winding of relay 3CRL, back con- Y n ytact of the make-before-break combination |33 Vof relay BCI-IO, vfrontcontact |96 of relay SCRL,

front contact Y2li of `relay t'I'FI and winding of relay Brez tonegativeA battery.Y aeiaysrez 0perates and closes a locking circuit foritself which includes its own front contact 2|5 and front con-A tact 2|2of relay SSAP. v This connection to positive battery also extends backtothe winding of relay SCRL for releasing this relay and. the release ofrelay SCR-L eiiects the release` of relay tcRLP. k During the intervalbetween the release of .relay SCRL and therelease of relay iiCRLP, thecounting relayleft operated is notreleased this time because frontcontact Zit of relay STF? maintains positivel battery on conductor |758.Since the station digits corresponding to the calling and calledtelephones have now been registered, the next operation is for thecalling subscriber to hang up the'receiver. This effects the release ofrelays 3GB andSSA in sequence..

Ringing relay ERI is now operated 4over Va cir'- phone of the callingstation, Which telephone is selectively responsive to the ten impulsesand the'V consequent operation .of register relays R4 `and Rt. Thisselection by the first ten impulses selects '56 cycle current andapplies it Vtothe tip side of the line, the return circuit t0 positivebattery being by way of the ring side of the line. This ringingcircuitmay be traced .from the'sourceof the 55 cycle ringingV current,front` contact 2|9 of relay Ril, front contact 22! of relay R6, backcontact 22| of switchingrelay SW, conductor 222,

' Winding of trip relay STR, front contact |"ii of 'relay BRI, conductoril@ and thence by way of Vthe selector and finder circuits to thetip'side of the line, through the substation ringer, back overthe ringside of the line and by Way of the V selector Vand finder circuits toconductorY |59, Y front contact |12 of relay BRI, conductor 223,

backco'ntact 224 of relay SW and iront contact 225 of relay R6 topositive'battery.

2 relay L of rt' is benevecnnnessary sessantenni-seein! 'all of thecombinations of :rel ayoperationsf for se'- lecing: other frequenciesand'or connecting-these frequencies over thev tipy or ring conductors of'f from tire five frequencies 116`v to' 66 cyclesinclusive to the .ringside of tneline ny wayor conductor |69. With register relay operated;the Acycle 'generator is connected by way'crthe teck contactsot therstftour registerrelays' series desc i ed toI the tip side' ofv theVline'. Further, Vit will be noted that the`Y next 'tour' frequencies areSelected and applied t0 the tip Side'` of the fllrie in response tothec'peratizlniofreiays 1,2,.13 .anu

. i# in combination with relay" '6, indicated Fig. 11A. f

"The '66 cycle current, overV this above described circuit, rings thebell ofthe calling station and when the reverting call inite'rrup'telContact RCI isc'losed) aA circuit is completed'tliroug-htliis Vcontact'and by Way of fron-t Contact 22B fof relay SRIlfcr operating relay SW".This connects the frequency selected in response tcitne called sta.-

ti'orr digit, vwlfilch in the abo-ve example Ywas #2 and which leftcounting relay 302i operated. Consequently, a circuit is closed from the'fcycle genera-tor common by Way of front vContact 221 of relay 302,back contact E23" of' rela-y 3GB; back contact 22's of. relay SCi, backVcontact 23vofffrelay BCS, back Contact 231i of relay BCS', frontcorrta'ctd of relay SW, conductor 722'31 front contact l'i2` or relaySRI andl conductor I'GQ to the ring 'Side' kofv the lne,'thereturnclrc-uit being way :of conductor front Contact 'VHA- ofr relaySRI', VWin-ding of relay STR, lconrluctor 222, front Contact 22| ofrelay SW and back conta-cttw of relay SC?? to positive battery. A t

"' t1 reverting call interrupts y operated for interni cnt-"ly onersw.theV ceiling emi canes stenen en either party responds, ne directcurrent pat across tl're telephone line ei tive to` operate relay 3TH.which, its iro t contact 233, short-circuits and releases relay ESAP;Relay SSA?, at its iront Contact 2135, opens the holding circuittoA thesleeve conducto-r, including. conductor P63, which f Walle-before-bzfeakcombination 235 of This effects the release' of the seiinder to whichthe calling line was i Neil as the release of the lockout this line..When the lockout relay releases, tne double wound line relay' isconnected across the calling line and it `operates to rnaintain thecut-off relay associated with this line its operated position, beiore ithas had' time to release, due to' its slow acting characteristics'.

Talking battery supplied to the line' through the windings of tile linerelay and, since theV finder has been released, no circuit is'held' inuse Y during a revertingV call talking corine'ctionrexcept that of theindividual line. *Relay L0 is maintained deenergized beceuse currentflows through its windings in oppc extending frein positive battery,iront Contact 25 of relay LR,`1c'-nt coi-itam', 25 of relay CO, lowerWinding of relay IAO', winding or` .relay C0 and Contact is extends topositive battery by way of back conf f ron', over a, `circuit and upperWinding of relay LO toI negativo batcon t upper' winding cfrelayc'@y tonegative battery. This maintains relay .CO operated and applies positivebattery to' sleeve'conductor S for .making this line busy.. When bothparties bang up, relay LR releases torestore the line circuit to normal.ioirnr-ionr reverting call sig-nal relay RC is operated when oneorIno're lines are locked out on a reverting call, over a circuitextending from positive battery, Winding of relay RC, front con- "L "noi rela-y CO; front Contact 25 o'frelay LR tery. The contacts of rela-yRC may be used to 'L t a la-inpv orto control any. desired. signalcircuit. 'Y

The release of relay BSAP removes" pos' battery from vallotter4conducto: BNL' et co t E ror rendering this re ting call kcir cuitawa/in' selectable; Thev op'ei c ci contact 2li. of relay SSAP effectsthe release of rele-.ys SIF, STFI, R and Rt. The' opening of front actEle of relay SAP effects the release of relays-3G@ and S'CS.- vRelay STRis released when the nder or selector disconnects thelinc circuit fromthev reverting call circuit.

`The circuits of this invention are arranged for 'two separate timerelease features. The first is an arret vement whereby aline witha'perm'snent signal automatically released from a link circuit, suoli.as the' connectorlink of Flits. 5 G, after a predetermined timeinterval'. The 'time release feature relates to conversation release,that is, after a predetermined interval, say live minutes, a Warningtone is given to the subscriber and 'then after en additional oneminute, they are automatically released from the link circuit. vThecommon time release cir-- cuit, as shown in' Figs. 8 and 9, illustratesthe common conversation' vtime release ar operating in connection withthe cour ing relays certain other relaysv which are assumed to Vbe thesaine* relays sliown in Figs.- 5 and 61 In other wor-els, whenconversation time release is desired it is connected into the circuitsof Figs. 5- and 5 in the manner 'illustrated in 9.

rThe ilrst or permanent signal time release arrangement Will noW bedescribed. When a link is seized, such as the connector link of Fig. 5or theV reverting call circuit of Figs. Il andlZ, positive battery isconnected to the timer ste-rt conductor 265 by Way of eti-ront contactof the SAP relay, su'ch as front' contact-235 oi relay SAP'cr frontContact' 2:58 of relay SSAP, and this positive battery on conductor '2&5is effective to operate the timer :start relay TSRWliiCh, at its irontcontact 231, closes a circuit for operatingv the timer motor. Positive'battery' is connected through front contact 2385 to cam `CMI whichiscontrolled b'y the time-rV moto-r and which is closed` every 21h-minutesfor approximately 2 At the beginning of each 21A-minute interval,

the interrupter cam closes'v a circuit for operating relay TSA and thisrelay closes an obvious circuit at its front contact 245 for operatingrelay TSAP. Relay TSA releasesat the end of the `21Ag--n1inuteintervaland connects .positive battery .through its back contact 24B toconductor 234.7by Way of front contact 244 of relay TSAP.

ngemcnt If the call has not been answered, back contacty 242 ci relay ABWill be closed and relay 2TM will be operated bythe application ofVpositive battery'to conductor 204. The operation of relay 2TM transfersthe. holding circuit of the sleeve conductor, including conductor 38,from positiveV battery atthe back contact of make-beforebreak springcombination 244 of vrelay 2TM,fto conductor Zwvhich has positive batteryconnectedfto-it atrback contact 245 lof relay TSA. Relay ETM alsotransfers the circuit extending to its Winding `from conductor 224 ktopositive battery atiront contactv or the make-beforebreak combination24%` of relay TM, for'locking' thisrelay when it is once operated..Consequent-- ly, when relay TSA releases at the beginriing' ofl azl-rninute interval, positive battery is applied to conductor 224 foroperating relay 2TM, butl at this saine time positivebattery is appliedvto conductor 253 at backcontact 245`for holding the connection totheline. v`At the-beginning lof the next 21A-minute interval,the'operationot relay TSA opens up the cir'cuitto positive battery onconductor 253 and this effects the releaseV It will thus be seen that,

of the connection. when a connector' link or Vthe like is being usedWithout the call being answered at the beginning of a 21A-minuteVinterval, the associated 2TM relay is operated and locked and thesubstitute holding circuit is connectedto the sleeve or holding circuitby way or conductor 253 and if this condition is maintained, that is,Without the circuit of theV 2Tlti relay being openedI during the next21A-minute interval, then the removal of positive battery from conductor203 eiec'ts the release of the connection-` t is .believed- 2TM isoperated over a circuit extendingfrorn positive battery at front contact2520i relay CTR,fconductor B, front contact 249 of..relay' 5TM, backcontact of the make-before-break combination 246 of relay 2TM,front-contact 248 of relay AB, frontcontact 241 of relay GTM,

front contact 239v of relay SAP and'winding ofl relay ZTM to negativebattery. This circuit isV closed at the beginning of the. cZL-minuteinterval when the cam CM2 is closed for operating relay CTR. Relay ZTMcloses allocking'circuit for ritself at the front contact off themake-befor'e- Y break combination 246 and atthe front Contact 244 ofrelay kZTli/l the holding circuit, including conductor l0,is`transferredfrom positive batobvious how the circuits of other connector links,selector links or reverting call circuits, Will operl ate in a likemanner by rneans oflfthe operation of the associated ZTM 0r STM relays.Thefre'-,

mover of positive battery from the holding circuit eects the release cirelay LO and the energization or" relays LR and CO ofjtheline circuit,

' as long as the permanent condition exists, all 'in the saine mannerpreviously described in connection vwith the locking out of the linecircuity cn a reverting call. u

It Will noW be explained how the conversation time release operates.`The 2TM relay ofA Fig; 5

is again illustrated in Fig. Sand an additional,

Vbination 246 of `relay 2TM, back contact 249 oi relay 5TM to conductor204. If the call is answered before vrelay ZTM is operated 'over thiscircuit, the operation of relay A B opens upthe above described circuitat its back'contact 248` and extends conductor 204 by Way of frontrcorntact 248 to front ContactV 241 oi relay lTM.V VVThis disables the iirsttime release circuit' and brings the conversation time release feature.

The operation of relay AB closesY avci'rcuit for operating relay GTMWhich extends from positive battery on conductor l1 of the connectorlink,

iront contact 2553 of relay'AB andwinding of relay EI'M to negativebattery.i The holding ,ciij cuit for the finder andselectorincludingjcon-A tery to positive battery through thecountingrelay contacts over'a circuit which extends throughy front contact 253'of relay 5TM, back'contact 254Y a of relay CS, back contact 255 orrelay C9,'back Y ContactV 256 of relay CO andV conductorl'i, Y.to whichpositive battery is connectedat front contact 95 of relay SAP of theconnector;link. `This means that positive battery will be held onholdingconductor l5 until relay C8 is operated to 'openits back contact254 and this is accom- Y plished in a manner which Willn-ow beexplained. It will be recalled that relay IR otFlg. 5 is momentarilyoperated Whentne calledr party answers. The operation of relay TR.eectstherelease of the counting vrelay which' was left 50p.'`

erated to select kthe ringing frequency. Thisis accomplished by openingup the locking circuit, including conductorll, at back contact ',258 orrelay TR. Then` when contact 268 againfcloses,

conductor I'Ivis again energized and' relay CX is,`

operated. When theFA-minute interrupter cam CM2 closes its contactforoperatingrelay CTR, a circuit is closed atits front-contact12,51v foroperatingrelay CC. Relay CC, at its front con-f tacts 258 and 259,applies positive battery to con` ductors 26| and 202 Which lead to frontcontacts` 260 and 26| of the BTM relay associated with thel link whichis lin use. It will be understood thatv ing relays in the manner whichhas already been explained by means of circuits including con.- ductorsH and I5 and I' This means that'a counting relay will bek operatorivevery T/gr-rninute and at the end of the seventh sAr-rninute (5l/4minutes) counting relay Cl willbe operated' and shortly thereaftercounting-'relay C5 lvvill'vbe released; YDuring this interval, atone'isconnected to the conversation circuit by way offrent 'con-r tacts 252and253 of lrelays Cl and Ct respectively and contacts 254 and 265ofrelaysV27PM and'A'B respectively, this tone being tinterruptedvvhenV relay C6releases. If the connection kis not re-l leasedat the beginning of theYnext %-niinute interval, the operation of-relay/CS ope'nsfitsy backcontact'254 to remove positivebattfery, whiclrison conductor l1, fromthe circuit leading through Y front contact 2.53 of relay STM and Virontcontact 25| or relay 2mm homing conductorm.- Thisv eiects the `release othe 'connection in the pre-g viously described manner andthe closedcircuit acrossY the lines of the 'released,stations*beingi ductor l0,novv` extends to positive battery by Wayj effective to lockout thoselinecircuits?, bypperatl Y

